It wasn't at all popular at uni, but one my teachers did use it and that's how I got to know it. Her use case was to write visualization programs in C/C++ and

It wasn't at all popular at uni, but one my teachers did use it and that's how I got to know it. Her use case was to write visualization programs in C/C++ and then have Tcl/Tk as the GUI with buttons, inputs, etc.